Instruments for cutting glass have long been known.
Generally, a support plane is foreseen on which the plate to cut is fixed. FIG. 1A shows such a support in accordance with the known art.
The support foresees a vertical arm forming a binary on which the cutting device slides from bottom to top and vice-versa.
Such a vertical arm is fixed to a horizontal arm and some oblique transverses connect the vertical arm to the horizontal arm in such a way as to form as a whole a support plane for the plate to cut. The vertical arm, which constitutes the sliding binary for the cutting device, creates a space between it and the oblique transverses in such a way that a plate can be positioned under it in the pre-chosen position.
The cutting device foresees a blade holder provided with a fixed cutting blade or a rotatable roller. Such a device is made to slide along the vertical binary until intercepting the plate to cut in such a way that, once the plate is intercepted, it continues its course passing through the plate, cutting it into two parts.
In accordance with this well-known technology, plates can be cut with thicknesses that measure in the order of some millimeters, for example from two to five millimeters.
In principle, for greater thicknesses are used different cutting machineries.
The cutting device is adjusted at such a height that the blade, during the sliding, intercepts the edge of the plate against which it hits to continue with the cut.
Having said that, a technical problem linked to the use of such cutting devices is that such a hit of the blade against the edge of the plate, or sharp edge, causes with time an early breakage of the blade itself, which has to be thus substituted frequently. Further, such hits can bring micro-fractures of the blade thread (of the cutting part of the blade) with an irregular wear. This is the cause, with time, of a quick loss of cutting capacity with the consequent need for a frequent substitution of the blade.